1. Field of the Invention
The present invention relates to an improved apparatus and method for forming an axle spindle on a hollow axle blank.
2. Description of the Prior Art
Spindles are formed on the ends of axle blanks in order to mount associated wheels, usually by anti-friction bearings that minimize friction during wheel rotation. Axle blanks on which the spindles are formed usually have a hollow configuration of a round tubular shape whose diameter must be decreased at its end or ends in order to provide various reduced diameter portions, axial ridges, and tapered frustoconical surfaces that define the axle spindle. A conventional method for forming such axle spindles is by hot forging at three work stations. Each work station incorporates a pair of split dies used in the forging. At the first station, the split dies grip the blank about its heated end and an axial upsetter is utilized to form the blank material to conform with the interior of the split dies. A hammer operation is performed at the second station by the split dies thereof, one die being mounted stationary with the heated blank supported thereby, and the other die being movably supported to pound the blank between the dies. Another axial upsetter is utilized at the third station to shape and size the blank between the split dies of this station.
Rough axle forgings made by the split die process described above must be machined in order to complete the spindle forming process. This machining usually requires a first semi-rough cut prior to a semi-finish cut that proceeds a finishing step during which the spindle is polished. Prior to the material removal during these machining steps, a parting flash that is caused by the split die construction must first be removed from the forged spindle as well as scale that builds up during the forging process. Care must be taken during this forging process to prevent internal voids from occurring in the forged axle spindle and to make sure that the inner and outer axle spindle surfaces are concentric with each other. Rotation of the axle blank between each pound at the second work station must be limited in order to prevent the internal voids from forming.
Axle spindle forming, forging and other forming, etc. are shown by U.S. Pat. Nos.: 2,053,975, 2,165,472, 3,165,199, 3,327,513, 3,465,418, 3,580,038, 3,668,918 and 3,673,888.